Isolation, Antioxidant Activity, and Reaction Mechanism of Chamazulene from Artemisia selengensis Turcz. ex Besser Essential Oil

High Resolution Image Download MS PowerPoint Slide Chamazulene is a blue azulene-type constituent with notable bioactivity, but its preparation from edible Artemisia and its antioxidant mechanism remain insufficiently characterized. In this work, chamazulene was isolated and purified from Artemisia selengensis essential oil obtained by steam distillation. The major volatile components, including eucalyptol, camphor, caryophyllene oxide, and chamazulene, were identified and quantified by GC-MS, and chamazulene was enriched by silica gel column chromatography and structurally confirmed by HR-MS, NMR, and FT-IR. The isolated chamazulene accounted for 5.17% of the essential oil with a purity of 98.5%. Chamazulene exhibited pronounced antioxidant activity in the ABTS assay (IC 50 = 5.04 ± 0.09 μg/mL). To elucidate its antioxidant mechanism, DFT calculations were carried out, revealing that chamazulene has a significantly lower ionization potential than BHT, supporting an electron transfer pathway for ABTS· + scavenging. The good agreement between experimental and theoretical results provides a mechanistic explanation for the strong antioxidant performance of chamazulene and highlights A. selengensis essential oil as a valuable natural source of this azulene-type antioxidant.